Aunt Karen

When the family decides to visit Francine's Aunt Karen in "The Last Ride of the Dodge City Rambler", they decide to do so by taking a costumed ride on a steam train on its final run before going into a museum. To Stan's annoyance, "Slob" joins them on the trip. Desperate to get out of the trip, Stan slips off the train during a stop and intentionally misses it, but when the engineer is shot and dies in his arms, he finds the 'train robbers' are real.

Stan catches up, but Francine refuses to listen to him. Stepping between cars to ponder his next move, he discusses his dilemma with a stranger who turns out to be a gang member and knocks him out. When he comes to, he finds he's been chained up and the gang intends to ram the train into the railroad headquarters. Even worse, they chain Aunt Karen up with him. The hijackers reveal that they are the descendants of the original land owners who were cheated by the railroad company. As they leave Stan and Karen alone, he uses Karen's oxygen tank to make a blow torch to cut their chains.

With a marble from a bag that Stan picked up when he left the train and Karen's oxygen tank, they place the tank at the edge of the firebox and uncouple the cars, hoping to use the marble to knock the tank in once they are clear. Unfortunately, the family distracts them at the critical moment and Stan can no longer take the shot. However, Aunt Karen takes the marble and makes the shot, blowing up the train just before it crashes into the railroad headquarters as the passenger cars slow to a stop. The remaining robbers are arrested, as the family decides to stay with Aunt Karen. However, she collapses, gasping for air due to her missing oxygen tank as they agree to take her to a hospital first.

Aunt Karen is voiced by Mindy Sterling.